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I have tried 2 other carbs, both did exactly the same thing, I'm looking at that and assuming that it is not a carb problem.


Actually I just realized that I haven't actually changed the fuel pump as I said I did. I hooked another up earlier on, but never replaced the one on the truck because I couldn't get the thing off and didn't want to drive it around with the new one just hanging there. I will try putting the new one on again tomorrow. I replaced the fuel filter already. Also, it's not necessarily that it won't drive under load, most of the time I can floor it when it threatens to die and it will maintain flow until everything goes back to normal and the truck seemingly runs perfect again, then I let up on the gas to remain at the desired speed.


I have cleaned out the fuel lines with an air compressor.

Alright, so now that the weather is kinda better here, how do i go about dropping the gas tank?

It seems like everyone is out of ideas but I thought I'd continue posting...

Truck still won't run, just replaced the fuel pump relay.
I'm trying to get the gas tank off, but frankly I can't see how it will come out anyway, it looks like there is just too much stuff in the way... I've only got one side unbolted, I don't have a lot of leverage for the other side and the bolts are pretty stuck.

Once I again I will say that I just purchased my first LUV recently so there are alot of other guys out here that know more about 'em than I do. Your fuel pump might be pumping enough for it to idle but not be able to keep up when it's under a load. I had a 1970 Datsun pickup 1600 way back that did the same thing. If I remember right it might have even had a mechanical pump (I'm not sure) but I kept having fuel problems so I installed an electric fuel pump under the hood and wired it to a toggle switch inside under the dash. This is a safety issue...if you're in an accident the fuel pump keeps pumping. You should be able to get a toggle switch for a few $$'s and if you have a few feet of wire around the garage would be all you need to see if the pump is keeping up under a load. That's a double edge sword because it can pump fuel pass the float and cause your engine to flood. Sorry but I've never tried to remove my gas tank.
Have you checked your timing? Point gap?
If you could list everything you have tried in one comment might be helpful. Good luck.

Karl

_________________
In life there is the "Way things should be" and then "There's the way they are".

2005 Silverado 3/4T Crew Cab
1981 Luv 2WD
1979 Luv 4x4 Currently going through Open Heart and Cosmetic surgery
1995 Roughneck JetBoat
1981 Luv parts trk

No, because everything was fine until it just stopped pumping gas properly. The engine runs great.

Did you ever replace the fuel pump?

_________________
In life there is the "Way things should be" and then "There's the way they are".

2005 Silverado 3/4T Crew Cab
1981 Luv 2WD
1979 Luv 4x4 Currently going through Open Heart and Cosmetic surgery
1995 Roughneck JetBoat
1981 Luv parts trk

My bad, I pulled the quote from the wrong entry.

_________________
In life there is the "Way things should be" and then "There's the way they are".

2005 Silverado 3/4T Crew Cab
1981 Luv 2WD
1979 Luv 4x4 Currently going through Open Heart and Cosmetic surgery
1995 Roughneck JetBoat
1981 Luv parts trk

on the oem carb there is a 1 wire solenoid on the passenger side of the carb with a needle and spring behind it.... this is so the carb can shut off the flow of fuel when the engine is off as an added safety measure in a rollover and to keep the engine from dieseling...
its called the anti dieseling solenoid... try removing the needle and coil then reinstalling the outer half... DO NOT OVERTIGHTEN as the case of the carb is cheap pot metal and stripps easily. this fixed my carb!!! hope it helps yours

Jake T

_________________
Government... if you think the problems we create are bad just wait till you see our solutions

Full status report here:

Replaced parts:
- Fuel Pump
- Fuel Filter
- Voltage Regulator
- Fuel Pump Relay

Parts Known To Be Problem Free:
- Carb
- Fuel Pump
- Fuel Lines (cleared with air compressor)

THE PROBLEM:
- Engine will start and run first go with enough fuel in tank (1 or 2 gallons)
- Will start (1-5 tries so far) with less but will run on fuel in bowl from starting and then slowly die.
- Truck will run without stopping assuming there is enough fuel in tank and it is sitting still on flat ground
- Truck will sputter and die when driven, regardless of amount of fuel

My thoughts:
Based on my troubleshooting and logic, I think there is just some crud floating in the tank and clogging the lines. I ran it very dry before filling up and the next day it stopped running. When I cleared the lines the first time, some junk came out.

Messing with the carb functionality with my experience seems a bit risky, so with all due respect to Jake T(auto4life), I will wait for another user to give confirmation that his solution is ok for a newbie to try.

I've gotten the front 3 bolts off of the tank already but can't seem to get the rear 3 loose. Any suggestions on how to properly remove the tank would be greatly appreciated. (I'd rather try Jake's solution first, but would like the above confirmation first.) This is my only vehicle and will have been down for a month on Sunday.

Thank you all for your suggestions and knowledge.
I have learned a great deal about the truck from all this.
- Caleb
541.337.2357

One more thought. Have you tried loosening or removing the gas cap to see if that helps? Otherwize I believe you may be right about some crud in the tank clogging up the inlet. A plastic bag floating in the tank for example.

What is the logic behind loosening the gas cap? Just out of curiosity, not meaning to be rude or anything, I'm just wondering, pressure change?

If it is a non-vented cap (or a vented cap with a clogged vent) and the evaporative emissions stuff is clogged up the tank could get a vacuum going in it with the pump sucking gas out of it. As vac builds in the tank, the pump would get less and less gas because the tank would be trying to suck in back in.

I've had to blow air through the fuel lines on a couple trucks to get the crap loosened up. My 79 had a couple dead yellow jackets in the tank that would just fit in the pickup line but not into the filter as well as a lot of junk that the little buggers left behind. Blowing air through the lines would temporarily fix the problem, but I evenually had to pull the tank and clean it out. If you blow from the pump or filter into the tank be sure to take off the cap so as not to pressurize the tank. It will spit gas back out the line otherwise.

I think just about every time I've pulled a LUV fuel tank I ended up snapping off the back bolts because they were so rusted. I used a socket on an extension with a wrench wedged on the top of the bolts to try to get them loose. If I recall correctly the front lip of the tank sits on the mount and the rear is held up by the bolts. I may have that backwards, its been a few years. Be prepared to have the tank fall when you get the last bolts loose. If it is full of gas it can be very heavy. (roughly 8lbs per gallon) I cleaned the last one I did out using the pressure washer through the sender unit hole at a local carwash and it came out fine. Most of the water will come out and once its clean set it someplace warmish and the rest will pretty much dry out. You can use a towel or rag on a stick if you want though.

_________________
95 Isuzu Trooper Daily Driver
86 Isuzu Trooper reliable backup
77 LUV 2wd stock beltway blaster (resting)
79 4x4 LUV project: 2.6L, 5spd, 31s (eventually)

MEPR: Man, my 4x4 makes all other LUVs look good

Finally got the damn gas tank off, I ended up just taking off the wheel and jacking it up so I could get the leverage I needed on the ratchet. Emptied about 5 gallons out of it, 2/3 was water and 1/3 was what appeared to be gas... It burned at least. I don't really know how that happened because I'm sure I pumped EVERYTHING out of there. Anyway, no crud in the tank, just a ton of water. I'm drying it out and putting it back in today.

The Adventure Thus Far:
- Replaced Fuel Pump
- Replaced Filter (Will do again.)
- Replaced Voltage Regulator
- Replaced Fuel Pump Relay
- Switched to different carbs a couple times
- Removed and cleaned the gas tank
- Cleaned out the lines with an air compressor. (will do again.)

Let me know if you've got any tips or ideas.
- Caleb
541-337-2357

ok i dont know if it was mentioned or not and you probably checked it out but... the fuel pump relay fuse... mine died one time going down the road and i almost got ran over a semi going about 80... i called my auto teacher and tried everything he said from jumping and messing with everything and it would start and idle great and when i went to take off it would die. or i could go just a little bit and it would die... turned out after toeing it behind my friends truck with a semi tow strap i found on the side of the road, about 40 miles back to my house. my grandpa came out and asked what was wrong i told him and the first thing he said was "did you check the fuse?" of course i hadnt thought i would be smart and call my auto teacher... turned out the fuse was starting to go bad and it was a little rusty on the posts...and when i pulled it and cleaned it off with a wire brush, replaced the fuse it ran great...

moral of the story big problems can be caused by little things.

of course if you changed all that you probably thought to check a fuse but thats my 2 cents

sorry if i come off sounding stupid

Chris

_________________
do you believe in LUV at first sight or does one have to drive by you again?

76' stepside mikado w/sunroof

I put the tank back in today and it ran great while idling... then i took it out to drive and it got the street a ways and died. it cant handle revving or acceleration but will idle forever... i need help guys, i have to either fix it or junk it today

Caleb
541.337.2357

Got to get it down to either fuel or electrical problem, as symtems can be similar.
If you have the Hitachi carb on try this-- with the engine at idle check to make sure the fuel level is half way across the little glass window. Then drive the truck and when the engine dies immediatly push in the clutch and coast to a stop. Before doing anything check the fuel level in the carb window again and see if it is still at the center of the window. This will tell you if is a fuel problem or not.
I assume you replaced the pump and the old one is not fuel line circuit at all? (The original pump has a fuel filter in the end of it that few people know about, just thought I'd ask).
A very weak spark can act the same way, engine will run but not take a load. Points and condenser ok and coil wired right? + to the ignition switch and - to the distributor?
Also remember that since the tank is now ok there may be some water still in the carburator bowl.
Good luck I'm pullin for ya!

I have seen a coil do this in the past. The vehicle would run until the coil got hot and then kill the engine. Does your engine start up again instantly after it dies? If so then I would guess that's not the problem. Did you ever check to see if your fuel cap is vented? Heck just to try it out take the fuel cap off and check it out to see if it runs...unless you live on a dirt road, that might give you some dust in the tank you just cleaned. Before I junked the truck I would wire the fuel pump to a toggle switch (bypassing the relay) and hotwire the coil to the battery to make sure you keep a spark at least out of the coil. I wouldn't leave it this way very long, only long enough to check to see if it makes a difference. Just a few things to check and it shouldn't cost hardly any money and really only a few minutes of your time.

_________________
In life there is the "Way things should be" and then "There's the way they are".

2005 Silverado 3/4T Crew Cab
1981 Luv 2WD
1979 Luv 4x4 Currently going through Open Heart and Cosmetic surgery
1995 Roughneck JetBoat
1981 Luv parts trk

Turns out I didn't have to get rid of it, so I'll be checking on your guys' ideas

Just curious...any progress?

_________________
In life there is the "Way things should be" and then "There's the way they are".

2005 Silverado 3/4T Crew Cab
1981 Luv 2WD
1979 Luv 4x4 Currently going through Open Heart and Cosmetic surgery
1995 Roughneck JetBoat
1981 Luv parts trk

Haven't really had a chance to work on it yet. Had a mechanic friend over tonight, he says it's most definitely the fuel pimp or something in the lines. So I'm gonna buy all new lines, which is probably a good idea anyway with all the ethanol these days, and the fact that they are all stock. And I'm gonna try a refurbished Holly my dad has sitting around. But I have no progress yet.